Canis ISSN: 2398-2942

Soft tissue sarcoma

Contributor(s): Laura Garrett, Jane Dobson

Introduction

  • Soft tissue tumors are tumors arising from mesenchymal connective tissues. They are usually grouped together as they generally behave in a similar manner. The benign mesenchymal tumors, eg fibroma, are locally expansile tumors that are cured by local surgical excision. These tumors by definition do not metastasize and they generally only cause clinical problems by their size or location. The malignant counterparts are generally referred to as ‘soft tissue sarcomas’ (STS) as they mostly present, behave, and are treated, in a similar manner.
  • STS account for 15-20% of all canine tumors: although incidence can vary according to breed - see below.
  • Signs: firm, fibrous mass affecting skin/subcutis, may be adherent to underlying tissue, slow growing.
  • Include:
  • Diagnosis: biopsy and histopathology.
  • Treatment: surgical resection +/- radiotherapy.
  • Prognosis: based on mitotic index and evaluation of margins.

Pathogenesis

Etiology

  • Largely unknown in dog.
  • Occasionally associated with chronic inflammation.
  • Rarely arise at sites of burns or implants.
  • Rarely radiation induced.

Classification

  • According to presumed tissue of origin based on histological appearance of neoplastic cells and stroma:
    • Fibrosarcoma - fibrous connective tissue*
    • Peripheral nerve sheath tumor (PNST)
    • Liposarcoma - adipose tissue
    • Leimyosarcoma - smooth muscle
    • Rhabdomyosarcoma - skeletal muscle
    • Myxosaroma - myxoid stroma
    • (Hemangiopericytoma Hemangiopericytoma - most now reclassified as PNST).
*When evidence of collagen formation is lacking, often referred to as ‘spindle cell sarcoma’.
  • Some poorly differentiated tumors which lack cellular / stromal features to indicate tissue of origin may be referred to as ‘poorly differentiated’ or ‘anaplastic’ sarcoma.
  • The following may also be described as soft tissue sarcoma, but are ‘excluded’ from the following general description / management because their biological behavior is more aggressive:
    • Synovial (cell) sarcoma
    • Histiocytic sarcoma - dendritic cell origin
    • Hemangiosarcoma - vascular endothelium.

Timecourse

  • Relatively slow growing.

Diagnosis

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Treatment

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Outcomes

This article is available in full to registered subscribers

Sign up now to purchase a 30 day trial, or Login

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Bray J P (2017) Soft tissue sarcoma in the dog - part 2: surgical margins, controversies and a comparative review.  JSAP 58 (2), 63-72 PubMed.
  • Bray J P (2016) Soft tissue sarcoma in the dog - part 1: a current review.  JSAP 57 (10), 510-519 PubMed.
  • Demetriou J L, Brearley M J, Constantino-Casas F et al (2012) Intentional marginal excision of canine limb sarcomas followed by radiotherapy. JSAP 53 (3), 174-181 PubMed.
  • Dennis M M, McSporran K D, Bacon N J et al (2011) Prognostic factors for cutaneous and subcutaneous soft tissue sarcomas in dogs. Vet Pathol 48 (1), 73-84 PubMed.


ADDED